| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| |
| package org.apache.samza.logging.log4j; |
| |
| import org.apache.log4j.AppenderSkeleton; |
| import org.apache.log4j.spi.LoggingEvent; |
| import org.apache.samza.diagnostics.DiagnosticsExceptionEvent; |
| import org.apache.samza.diagnostics.DiagnosticsManager; |
| |
| |
| /** |
| * Provides an in-memory appender that parses LoggingEvents to filter events relevant to diagnostics. |
| * Currently, filters exception related events and updates the {@link DiagnosticsManager}. |
| * |
| * When used inconjunction with {@link org.apache.samza.metrics.reporter.MetricsSnapshotReporter} provides a |
| * stream of diagnostics-related events. |
| */ |
| public class SimpleDiagnosticsAppender extends AppenderSkeleton { |
| |
| // simple object to synchronize root logger attachment |
| private static final Object SYNCHRONIZATION_OBJECT = new Object(); |
| protected final DiagnosticsManager diagnosticsManager; |
| |
| /** |
| * A simple log4j1.2.* appender, which attaches itself to the root logger. |
| * Attachment to the root logger is thread safe. |
| */ |
| public SimpleDiagnosticsAppender(DiagnosticsManager diagnosticsManager) { |
| this.diagnosticsManager = diagnosticsManager; |
| this.setName(SimpleDiagnosticsAppender.class.getName()); |
| |
| synchronized (SYNCHRONIZATION_OBJECT) { |
| this.attachAppenderToRootLogger(); |
| } |
| } |
| |
| private void attachAppenderToRootLogger() { |
| // ensure appender is attached only once per JVM (regardless of #containers) |
| if (org.apache.log4j.Logger.getRootLogger().getAppender(SimpleDiagnosticsAppender.class.getName()) == null) { |
| System.out.println("Attaching diagnostics appender to root logger"); |
| org.apache.log4j.Logger.getRootLogger().addAppender(this); |
| } |
| } |
| |
| @Override |
| protected void append(LoggingEvent loggingEvent) { |
| |
| try { |
| // if an event with a non-null throwable is received => exception event |
| if (loggingEvent.getThrowableInformation() != null) { |
| DiagnosticsExceptionEvent diagnosticsExceptionEvent = |
| new DiagnosticsExceptionEvent(loggingEvent.timeStamp, loggingEvent.getThrowableInformation().getThrowable(), |
| loggingEvent.getProperties()); |
| |
| diagnosticsManager.addExceptionEvent(diagnosticsExceptionEvent); |
| } |
| } catch (Exception e) { |
| // blanket catch of all exceptions so as to not impact any job |
| System.err.println("Exception in logging event parsing " + e); |
| } |
| } |
| |
| @Override |
| public void close() { |
| // Do nothing. |
| } |
| |
| /** |
| * Returns false since this appender requires no layout. |
| * @return false |
| */ |
| @Override |
| public boolean requiresLayout() { |
| return false; |
| } |
| } |